Intravenous (IV) fluid warming devices are known that heat an IV fluid prior to introducing the fluid into a patient. Warmed IV fluids that are administered at very low flow rates can cool as they flow down the IV tubing to the patient. Often this heat loss is ignored. One prior art approach has been to simply heat the fluid to 41 degrees C. to try to overcome the loss for all flow rates.
In another aspect of fluid warming, most IV fluid warmers heat fluid through flexible plastic walls. Because these walls are inefficient in transferring heat, heaters are exposed to both sides of the disposable set. This requires inserting the disposable set into a slot or hinged clam shell configuration. Both of these designs do not allow the user to see the fluid passing through the heat exchanger. As these plastic walls are flexible, the pressure necessary for good heat transfer cannot be guaranteed as it is supplied only by the gravitational force of the IV fluid bag height. Cleaning of configurations with slots is difficult and typically requires special tools or even disassembly, such as in the case of blood spills.
One type of exemplary medical fluid warming system is described in U.S. Pat. No. 7,158,719, the disclosure of which is incorporated by reference herein. In this device, fluid passes along a generally serpentine fluid flow path through a removable/disposable heat exchange body. The heat exchange body is in thermal contact with a resistive film heater via thermally conductive layers interposed between the heat exchange body and the heater. Temperature sensors are provided that sense the temperature of the heat exchange body and of the heater.